Abstract: At present, PET/CT (or PET/MRI) is a powerful imaging technique with the highest sensitivity and spatial resolution for the early diagnoses of major diseases, such as cancers. PET/CT (or PET/MRI) relies on PET radiopharmaceuticals, especially heavily relies on ¹⁸F PET radiopharmaceuticals. However, with a market approval of FDA for the first ⁶⁸Ga radiopharmaceutical (⁶⁸Ga DOTATATE) in the world, ⁶⁸Ga and its radiopharmaceuticals receive more and more attention. In this review article, firstly, basic nuclear characteristics and chemical properties of gallium were described. Secondly, the requirement of design for bifunctional metallic chelators was suggested. Then, the advantages and disadvantages of some common gallium chelators were discussed. Due to the high affinity and selectivity of 3-hydroxy-4-pyridinones (3, 4-HPs) to Ga(Ⅲ), the newest progress of 3-hydroxy-4-pyridinone multidentate chelators, which were used in gallium radiopharmaceuticals, was focused on. Finally, the prospects of 3-hydroxy-4-pyridinone multidentate chelators in gallium radiopharmaceuticals were also proposed.